Anquan Boldin to Battle Patrick Peterson

The 49ers No. 1 wideout will match up one-on-one with the Cardinals No. 1 cornerback for the first time since the latter was a rookie in 2011.

When tight end Vernon Davis is off the field, wide receiver Anquan Boldin has seen cornerbacks “roll” toward him, creating a double-team. In the words of their 49ers coach, Jim Harbaugh, this fact has been well documented.

But Boldin, San Francisco’s leading receiver with 393 yards through five games, faces a one-on-one challenge come Sunday at Candlestick Park.

Expect Arizona Cardinals corner man Patrick Peterson to get less help from his teammates.

“A lot of defensive backs don’t have the ball skills that he has,” Boldin said. “He’s one of their key guys.”

At 23, Peterson is also one of few mainstays. Six of Arizona’s nine defensive backs are in their first year with the team.

“I don’t know any of those guys… Not a lot of familiarity,” said Boldin, who spent the first seven years of his career playing for the Cardinals before collecting 145 receiving yards against them as a Baltimore Raven in 2011, when Peterson was a rookie. “I do think they have some talent on the back-end.”

The Cardinals agree. Both Peterson and his coach, Bruce Arians, have said they believe he’s the NFL’s best cover-man. 49ers offensive coordinator Greg Roman said Peterson, who has picked off three passes in his last two games, is “playing at a high level.”

Peterson has drawn tough assignments to prove it, guarding the likes of the Detroit Lions Calvin Johnson and the New Orleans Saints Marques Colston.

Boldin is next, and one of his few friends remaining in Arizona, fellow wideout Larry Fitzgerald, gives Peterson a daily dose of matching up with a No. 1 wideout.

“It’s been great for him,” Arians said of Peterson’s interactions with Fitzgerald since entering the league. “Larry’s a great pro, comes to work every day. Patrick has that same work ethic, he came in and solidified this is how you do it if you really want to be great.”

Said Boldin: “If you have a guy like that you go up against every day you have no choice but to get better.”

John Skelton, whom the 49ers signed last week before waiving on Wednesday, spent the past three seasons with the Cardinals. Since watching Peterson’s first of four punt return touchdowns during his rookie campaign – Peterson still returns punts and has since made cameos on offense – Skelton took notice of then-teammate's desire to become, first and foremost, a counted-on cornerback.

“Day in and day out in practice, he was up to the challenge of guarding Larry and being opposite of Larry,” Skelton said Tuesday. “He’s one of those guys where if Larry beats him on a route, he’ll come back to Larry and say, ‘Hey, Larry, what did you do there or see to attack me?’ He’s a always trying to learn, he’s always trying to get better. From my time there, I could see him evolve from when he first started playing corner to where he is now, and he’s doing a really good job.”

For his part, Boldin said he isn’t concerned with the kind of gaudy numbers he put up in his last game against his first employer. The opposing defense – in this case, the Cardinals – dictates whether Roman and Co. emphasize the pass over the run or vice versa.

“Each defense that we play against poses a different challenge,” the 11-year vet said. “Some weeks we’ll throw more, some weeks we’ll run more.